I have been killing like dozens of animals on my world with the typical flint n steel+sword combo and suddenly I just realized the fire was still there, even after several minutes. Yes, my extreme hills biome is now a second ripoff nether. It happened over grass, wood, stone, and several nether blocks (which I don't know if ALL of them are intended for permaburn). Experimental play turned on. Hard difficulty. Tick speed and all world options are default.

Cheers, CleaveGodz.

PD: I know there are multiple reports, but I also have this gold non smeltable thingy, good thing I started in a warped forest with no piglins on sight..